The city Medical Examiner has classified the Aug. 19 death of a Rikers Island inmate who swallowed a ball of laundry detergent as a homicide, the Voice has learned.

The death of Jason Echeverria in the Mental Health Assessment Unit in the George R. Vierno Center is believed to be the first homicide on Rikers since 49-year-old Angel Ramirez died on July 17, 2011 after being struck by a correction officer during a scuffle.

Echeverria's death was initially thought to be a suicide, but the ME had not completed its investigation until this week. Ellen Borakove, a spokeswoman for the ME, declined to comment beyond confirming the cause and manner of death.

People familiar with the incident tell the Voice that the death became a homicide because after Echeverria swallowed the soap, a correction officer notified his captain but staff did nothing to treat him for some time. That failure to act allegedly led to his death, they said.

The news left Echeverria's father, Ramon, at a loss for words. "I leave it in God's hands," he told the Voice. "I can't bring him back. I'm not saying he was an angel, but you don't let people die that way."

He added that the Correction Department never kept him informed of the progress of the investigation into his son's death. "They never talked to me," he said. "I only heard from a preacher, and he just told me my son was dead. That was it."

"The Department of Corrections notifies the DA and DOI of every death in detention, as it did in this case, and is cooperating fully with the investigation," a Correction Department spokesman said.

We asked a spokesman with the Bronx District Attorney late yesterday whether prosecutors are looking into filing criminal charges in the death, but did not hear back.

The Mental Health Assessment Unit, or MAUI, is a punitive segregation unit for inmates with psychiatric issues who have violated jail rules. Advocates have criticized the use of punitive segregation cells for people with mental illness. Others within the system have warned about the potential danger of the detergent balls.

Ramon Echeverria says he has retained a lawyer and is considering his legal options.